The present invention relates to a container, in particular a container for an ophthalmic lens, more especially, a container for a hydrophilic or xe2x80x9csoftxe2x80x9d contact lens.
Packages for storing, transporting and dispensing soft contact lenses may comprise a container having a cavity in which the contact lens is housed in a saline solution.
EP-A-0 223 581 describes such a package. The base of the cavity has an inclined surface to aid removal of the lens.
EP-A-0 604 177 also describes such a package. The base of the cavity is concave, and has a radius of curvature which is greater than the radius of curvature of the lens, while being sufficiently small to cause the lens to settle at the lowermost portion of the base, i.e., to centre.
Soft contact lenses are generally manufactured by moulding. After moulding, the contact lens is subjected to various hydrating, washing and conditioning processes. In order to minimise handling of the lens, it is desirable to carry out those processes while the lens is in its final package, that is, while the lens is in the container. However, it is then necessary to be able to introduce and to remove treating fluids from the container without damaging the lens.
Fluid may be introduced to the cavity in which the lens is housed by directing the fluid into the centre of the upturned lens, and then allowing the fluid to overflow into the cavity. (Contact lenses are usually concavoxe2x80x94convex; in this specification a lens is described as xe2x80x9cupturnedxe2x80x9d when its concave face is uppermost.) This method of fluid introduction avoids damage to the lens, and has the added advantage that it locates the lens at the base of the cavity, and prevents it from floating in the fluid.
Avoiding damage to the lens on fluid removal, however, is more difficult, particularly where the maximum diameter of the cavity is not much greater than the diameter of the lens. This will often be the case as it is desirable to minimise the size of the cavity in order to minimise manufacturing costs and production time, and to aid lens extraction by the user.
EP-A-0 618 063 describes a nozzle for removing fluid from a container containing a lens. The nozzle includes a fluid entrance passage and at least one fluid exit passage. The nozzle is placed in sealing contact with the container. Purging fluid is introduced to the container through the fluid entrance passage so that the fluid in the container is forced out through the fluid exit passage. The arrangement of the fluid entrance passage and the fluid exit passage is such that fluid flow is symmetrical about the central axis of the lens, so preventing migration of the lens from the centre.
It is an object of the present invention to provide a container which minimises or prevents damage to a lens on removal of fluid from the cavity housing the lens.
The present invention provides a container comprising at most two first cavities for receiving an ophthalmic lens, and a second cavity for the removal of fluid from the or each first cavity, the second cavity being laterally spaced from, and in communication with, the or each first cavity, wherein each cavity has an opening on the same face of the container.
Fluid removal is carried out by inserting a fluid removal device into the second cavity, either from above or from below, and then withdrawing fluid through the device. Insertion of the device in the second cavity avoids contact between the device and the or each lens, so reducing the possibility of damage to the or each lens. It will be appreciated that the second cavity may also be used to accommodate other devices used in the hydrating, washing or conditioning processes, for example, an ultrasonic probe to agitate the fluid, a device to heat the fluid, or a device to measure the fluid level.
The invention further provides a container comprising at most two first cavities for receiving an ophthalmic lens, and a second cavity for the removal of fluid from the or each first cavity, the second cavity being laterally spaced from, and in communication with, the or each first cavity, wherein each cavity has an opening, the openings being such that the cavities are capable of retaining fluid even when the openings are not sealed.
The invention further provides a container comprising at most two first cavities for receiving an ophthalmic lens, and a second cavity for the removal of fluid from the or each first cavity, the second cavity being laterally spaced from, and in communication with, the or each first cavity, wherein each cavity has an opening, the openings being such that the cavities form a closed system when the openings are sealed.
The invention further provides a container comprising at least one first cavity for receiving an ophthalmic lens, and a second cavity for the removal of fluid from the or each first cavity, the second cavity being laterally spaced from, and in communication with, the or each first cavity, wherein each cavity has an opening on one face of the container, the cross-sectional area of the opening of the or each first cavity being greater than that of the second cavity.
Soft contact lenses are subject to an inspection process as well as to hydrating, washing and conditioning processes. In the inspection process, an illuminating beam is transmitted through the lens. That beam is then focused on a screen to produce an image of the lens. That image is inspected (by eye or automatically) to determine whether or not the lens contains any irregularities which would make the lens unacceptable for consumer use.
In order to minimise handling of the lens, it is desirable to carry out the inspection process while the lens is in the container. Where that is the case, however, it is important to minimise the optical power of the base of the first cavity to minimise the effect that the container has on the illuminating beam. The base of the first cavity has zero optical power when it is flat. However, some curvature of the base is desirable to cause the lens to centre consistently. Accordingly, at least the lower portion of the inner wall of the or each first cavity is preferably concave.
The invention further provides a container comprising at least one first cavity for receiving an ophthalmic lens, and a second cavity for the removal of fluid from the or each first cavity, the second cavity being in communication with the or each first cavity, wherein at least a lower portion of the inner wall of the or each first cavity is concave.
Preferably, the second cavity is laterally spaced from the or each first cavity.
Where the lower portion of the inner wall of the first cavity is curved, it is desirable to maximise the radius of curvature of that portion to minimise the optical power of the base of the cavity. However, if the radius of curvature of the whole of the inner wall of the first cavity is such that it is just sufficient to cause the lens to centre, the first cavity would have to be extremely large in order to contain sufficient fluid to cover the lens. Accordingly, the inner wall of the or each first cavity advantageously comprises an upper portion and a lower portion, the radius of curvature of the lower portion being greater than the radius of curvature of the upper portion. This allows the first cavity to have a base of low optical power, while being able to contain sufficient fluid to cover the lens.
Preferably, the radius of curvature of the lower portion is between 9 mm and 35 mm. If the radius of curvature of the lower portion is less than 9 mm, the lens may not sit with its centre touching the centre of the lower portion. If the radius of curvature is greater than 35 mm, the lens may not centre.
Preferably, the radius of curvature of the upper portion is such that the maximum diameter of the or each first cavity is between 15 mm and 30 mm. A diameter that falls within this range allows sufficient volume for washing, while minimising package size.
Preferably, the depth of the or each first cavity is between 6 mm and 12 mm. A depth that falls within this range ensures that the entire lens will be covered by solution, while providing for the user the convenience of a shallow cavity.
Preferably, a channel provides the communication between the or each first cavity and the second cavity.
Efficiency of fluid removal will be greatest where the or each first cavity, the second cavity and the channel are all of equal depth. However, where this is the case, and the inner wall of the first cavity is concave, the channel walls will extend into the centre of the first cavity.
If the channel walls extend into the first cavity the discontinuity at their upper edges deflects an illuminating beam being transmitted through the base of the cavity. Such deflexion may be interpreted as being caused by an irregularity in the lens being inspected, particularly where the maximum diameter of the first cavity is not much greater than the diameter of the lens.
Accordingly, the diameter of the or each first cavity is preferably at least 15 mm where the bottom of the or each channel joins the or each first cavity. This diameter is slightly larger than the maximum diameter of a contact lens, and thus the channel walls will not extend far enough into the first cavity to cause any disturbance in the lens image during the inspection process.
The second cavity may be of any depth. Preferably, however, the depth of the second cavity is substantially the same as the depth of the or each first cavity.
If the diameter of the first cavity where the bottom of the channel joins the first cavity is as described above, and the inner wall of the first cavity is concave, then the depth of the channel where it joins the first cavity must be less than the depth of the first cavity. Although the depth of the channel where it joins the first cavity is advantageously less than the depth of the first cavity, the rest of the channel may be of any depth, for example, it may be of the same depth as where the channel joins the first cavity. Preferably, however, the bottom of the or each channel slopes downward from the or each first cavity to the second cavity.
In certain embodiments, the side walls of the or each channel are curved. In other embodiments, the side walls of the or each channel are straight.
The width of at least a portion of the or each channel may be less than the width of the second cavity. For example, where the side walls of the channel are curved, they may provide a constriction midway along the channel""s length. Alternatively, where the side walls of the channel are straight, the channel may be narrower than the second cavity, thus providing a constriction along the whole of the channel""s length.
The width of at least a portion of the or each channel may be approximately equal to the width of the second cavity. For example, the side walls of the channel may be straight and of the same width as the second cavity, thus minimising fluid velocity through the channel, and reducing the likelihood of the lens being pulled into the channel.
Preferably, the minimum width of the or each channel is between 3 mm and 6 mm. A width within this range is great enough to permit fluid to flow sufficiently rapidly between the first and second cavities when the fluid removal device is in operation, while preventing the lens from becoming wedged in the channel during or after processing.
The second cavity may be of any diameter, provided that it is sufficiently wide to receive the fluid removal device. Preferably, the diameter of the second cavity is as small as possible so as to minimise the size of the container, and thus minimise manufacturing costs.
Preferably, the container comprises a flange which surrounds the cavities. The flange provides a convenient grip for the user on opening the package, and a surface on which to seal a cover for the first and second cavities once a lens has been treated and inspected, and is housed in saline solution, ready for use. To gain access to the lens, the user peels the cover off the resulting package.
Advantageously, the flange comprises a finger or thumb tab. This is a depressed portion of the flange, adapted to receive a finger or a thumb. The finger or thumb tab provides enhanced grip for the user, and is particularly useful when the package is being opened in a wet environment. Preferably, the depth of the thumb tab is such that it provides a support for the container. This will improve the stability of the container.
Alternatively, or in addition, the flange may comprise one or more grips. The grips provide resistance to slippage, and, again, are particularly useful where the package is being opened in a wet environment. Preferably, grips are provided on the finger or thumb tab. Advantageously, grips are provided on both sides of the finger or thumb tab.
Preferably, the container comprises a protector ring on the outer wall of the or each first cavity. Any damage to the outer wall of the first cavity will affect the inspection process. The protector ring reduces such damage. Advantageously, the free edge of the protector ring is substantially planar. The protector ring then provides a flat surface for the container to rest on so improving the stability of the container.
The container is advantageously of plastics material. The container may be made by injection moulding or thermoforming. The plastics material may be, for example, polyethylene, polypropylene or polystyrene. Depending on the type and grade of plastics material selected, the container may be opaque, translucent or, preferably, transparent in view of the desirability of inspection of the lens in the container, as described above. The container may be made of a single material or a multi-layer material so allowing optimisation of the interior and exterior surfaces of the container according to function.
Preferably, the inner wall of the or each first cavity comprises a meniscus control means. The meniscus control means alters the effect of surface tension between the inner wall of the first cavity and fluid in the first cavity to prevent the meniscus of the fluid from interfering in the inspection process. The meniscus control means may comprise an alteration in the surface of the inner wall of the first cavity, for example, treating the surface by flame, corona or chemical treatment, altering the texture of the surface, or including a geometric pattern in the surface.
The present invention also provides a package for an ophthalmic lens comprising a container, the container comprising at least one first cavity for receiving an ophthalmic lens, and a second cavity for the removal of fluid from the or each first cavity, the second cavity being in communication with the or each first cavity, wherein each cavity has an opening, and the openings are sealed with a releasable film.
The present invention further provides a multi-pack for storage of a plurality of ophthalmic lenses comprising a plurality of containers, each container comprising at least one first cavity for receiving an ophthalmic lens, and a second cavity for the removal of fluid from the or each first cavity, the second cavity being in communication with the or each first cavity, wherein each cavity has an opening, and the openings of other containers sealed with a releasable film.
The multi-pack may contain, for example, seven containers for one week""s supply of daily disposable lenses.
The present invention further provides the use of a container for inspection, processing and storage of an ophthalmic lens, the container comprising at least one first cavity for receiving an ophthalmic lens, and a second cavity for the removal of fluid from the or each first cavity, the second cavity being in communication with the or each first cavity.